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BIAB Volumes - Sparge


New Forum Member
Mar 7, 2023
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Hey there,
I am going into brewing at bigger volumes, because my recipes which I use are tested and I dont have to worry about wasting too much grains if it turns out it tastes horrible.
I was going with the BIAB - method - just put all the water in, add the grains, yady yady yada. Unfortunately that wont work with bigger batches - my boiler is 31l (fermenter is 32litres, so I dont have to worry about putting 25l of wort into it), but I am a bit confused on how to set this up in beersmith.
Lets say i want to brew 25litres - have the recipe all scaled up and have the equipment profile edited to have my mash tun volume at 31L. So when I go into the mash tab - what should I choose? Personally I want to do it the easiest way, as I would have the sparge water heating up on the stove, so i want to use as little of it as I can get away with. I can always calculate it by hand - lets say its saying I need to put in 33,24l - obviously too much, so I put in 29l, mash in and then after 60mins of mashing I take the bag out and have the rest of the water - in this case 4,24l ready and heated and run it over the grains (i have an oven rack I put on the boiler to hold the grains). The estimated pre-boil volume is 29l so there should be no problem fitting in the boiler, right?
But is there a way to set it up like this in beersmith? I saw people saying you should use single infusion, full body, no mash out or batch sparge, but I got a bit confused by it tbh...


Grandmaster Brewer
Mar 16, 2013
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New Hampshire, US
In BeerSmith, the use of a BIAB mash indicates to the software that you are adding the full volume of water required to the mash. Once you start adding a sparge step, regardless of why, you need to switch your mash profile to a standard mash profile which allows the software to calculate a volume for the mash and add the remainder of needed volume as sparge water.

Once you do this, you will need to determine what water to grist ratio you want to use for the mash. There are a lot of thoughts in how much you should split between mash and sparge, but you can do whatever works for you.

On your sparge technique you outlined, I would recommend for consistency in being able to repeat a process step that you give the mash the full 60 minutes with the grain. Then you can lift the bag and pour your sparge water over the top of the grains. You really want to have the mash step optimize the conversion and extraction of sugars and that depends a lot on the quality of the crush and the amount of time it takes for the mash water to penetrate the grain particles and solubilize the starches.

The sparge step is intended to rinse the sugar rich wort from the grains. If you remove the grains before the mash water has the chance to dissolve the starches, you will be leaving a lot of gravity potential left in the grains.